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Explain how human ear works in the transmission of sound wave to the brain
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0
|
1373
|
July 1, 2016
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|
What is 'Ultrasound'? Explain how dejects in a metal Mock can detected using ultrasound
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0
|
2452
|
July 1, 2016
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|
(i) What causes reverberation of Thunder sound ? (ii) A SONAR device on a submarine sends a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m
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0
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1662
|
July 1, 2016
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(i) What does the acronym SONAR stand for ? (ii) What is the audible range of sound for human beings ? (iii) How do the bats search and catch their prey in dark night?
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0
|
811
|
July 1, 2016
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|
(i) How the bats make use of ultrasonic waves to catch their prey ? Explain. (ii) A radar signal is reflected by an aeroplane and is received 2 x 10^-5 s after it was sent. If the speed of these waves is 3 x 108 m s^-1, how far is the aeroplane?
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0
|
985
|
July 1, 2016
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(i) Even if a loud explosion were to take place at any place on the moon, it would not be heard at a nearby point. Give reason. (ii) Explain in brief the dependence of speed of sound on nature of material medium and temperature
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1
|
2645
|
July 1, 2016
|
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Why the astronauts talk to each other through radio telephone?
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0
|
3241
|
July 1, 2016
|
|
Give four practical uses of ultrasonic vibrations
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0
|
2397
|
July 1, 2016
|
|
State three conditions necessary for sound to be heard
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0
|
6594
|
July 1, 2016
|
|
A continuous disturbance is created on the surfacd of water in a ripple tank with a small piece of cork floating on it. Describe the motion of cork. What does it tell about the disturbance?
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0
|
2514
|
July 1, 2016
|
|
What is Galton's whistle? To what use it can be put?
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0
|
2768
|
July 1, 2016
|
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(a) State the law of conservation of energy. (b) What is the work done to increase the velocity of a car from 36 km h^-1 to 72 km hr^-1 if the mass of the car is 1500 kg ? Does the work done by the . force have a negative or a positive magnitude?
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|
1
|
5020
|
July 1, 2016
|
|
(a) Derive an expression for kinetic energy of a body having mass m and moving with a velocity v. (b) When velocity of a body is increased 5 times, what is the change in its kinetic energy ? (c) Two masses m and 2m are dropped from heights h and 2h. O
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1
|
4285
|
July 1, 2016
|
|
(a) Give two conditions for work to be done. (b) What is the work done by frictional force on an object when dragged along a rough surface ? (c) Relate power and work. (d) A machine does 1960 joule of work in 4 minutes. What is the power?
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0
|
2636
|
July 1, 2016
|
|
(a) Two bodies have equal masses and are moving with uniform velocities oflv and 3v. What is the ratio of their kinetic energies ? (b) A mass is dropped from height h. At halfway to the ground, what is the total energy?
|
|
0
|
1015
|
July 1, 2016
|
|
(a) What is meant by mechanical energy ? State its two forms. State the law of conservation of energy. Give an example in which we observe a continuous change of one form of energy into another and vice-versa
|
|
1
|
8821
|
July 1, 2016
|
|
(i) State the law of conservation of energy. (ii) Show that the energy of a freely falling, body is conserved
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|
0
|
20696
|
July 1, 2016
|
|
(i) A light and a heavy object have the same momentum. What is the ratio of their kinetic energies. Which one has a larger kinetic energy?
|
|
1
|
2501
|
July 1, 2016
|
|
(a) Define average power. Calculate the total energy consumed in the month of November in a household in which four devices of power 500 W each are used daily for 10 hours
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|
1
|
1868
|
July 1, 2016
|
|
(a) A person is holding a bucket of water by applying a vertical force of 100 N. He first moves a horizontal distance of 5 m and then climbs up through stairs a vertical distance of 10 m. Calculate the total work done the person on the bucket
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|
1
|
5600
|
July 1, 2016
|
|
(i) An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the total work done against the force of gravity
|
|
1
|
7009
|
July 1, 2016
|
|
(a) State law of conservation of energy. (b) Establish the relation between SI unit of energy and commercial unit of energy
|
|
1
|
760
|
July 1, 2016
|
|
(a) Define work. State two factors on which the magnitude of work depends. (b) A car and a truck have the same speed of 30 m s^-1. If their masses are in the ratio 1:3, find the ratio of kinetic energy?
|
|
0
|
4853
|
July 1, 2016
|
|
(a) Define the term 'average power'. (b) When a player hits a football, it moves along the curved path and then falls to the ground, Calculate the work done by the force of gravity on the football
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|
1
|
999
|
July 1, 2016
|
|
(a) The earth, moving around the sun in a circular orbit, is acted upon by a force and hence work must be. done on the earth by the force. State whether the statement is correct or not. Give reasons for your answer
|
|
1
|
4572
|
July 1, 2016
|
|
An object of mass 10 kg is made fall freely from a height of 10 m. Complete the table:
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|
1
|
2710
|
July 1, 2016
|
|
(a) Define work done by a constant force on an object. Write an expression also for the work done. (b) How much work will be done on an object by a force if the displacement of the object is zero?
|
|
1
|
4479
|
July 1, 2016
|
|
(a) State law of conservation of energy. Explain it with one example
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|
1
|
751
|
July 1, 2016
|
|
(i) Give the SI unit of power. (ii) What is the commercial unit of energy ? (iii) An electric heater is rated 1500 W. How much energy does it use in 10 hours?
|
|
0
|
882
|
July 1, 2016
|
|
(i) Derive an expression for the kinetic energy of an object. Write the SI unit of kinetic energy. (ii) An object of mass 10 kg is moving with a uniform velocity of 5 m s^-1. Calculate the kinetic energy possessed by the object
|
|
0
|
6188
|
July 1, 2016
|